[Comparative study of the diagnostic value of new cholera eltor bacteriophages ctx+, ctx-, and KhDF-3, 4, and 5]. / Sravnitel'noe izuchenoe diagnosticheskoi tsennosti novykh bakteriofagov kholernykh él'tor ctx+, ctx-, i KhDF-3, 4, 5]

The comparative evaluation of the diagnostic value of new cholera eltor bacteriophages ctx+ and ctx-, as well as monophages X[symbol: see text]-3, 4, 5, demonstrated their high activity and specificity. Using of these bacteriophages epidemic potential of 95% Vibrio cholerae eltor strains ctx+ and 84.5% of V. cholerae eltor stains ctx- was determined. Commercial monophages X[symbol: see text]-3, 4, 5 were inferior to bacteriophages ctx+ and ctx- in their diagnostic value: only 55% of strains having gene ctxAB were found to be epidemically dangerous, i.e. 45% of strains capable of causing the disease were not detected. On the basis of the results obtained in this investigation cholera eltor bacteriophages ctx+ and ctx- were recommended for introduction into practical use, while further production of cholera diagnostic monophages X[symbol: see text]-3, 4, 5 was recommended to be stopped.

[Phenotypic analysis of two morphologically different types of Vibrio cholerae 0139 colonies]. / Fenotipicheskii analiz dvukh morfologicheski raznykh tipov kolonii Vibrio cholerae 0139.

A clinical isolate Vibrio cholerae P16064 serogroup 0139 was shown to produce two different kinds of colonies: opaque encapsulated and translucent devoid of capsule. Low virulence of translucent colonies seems to be due to not only loss of capsule which determines serum resistance, but also to decreased expression of genes controlling the motility, and production of protease and mannose-sensitive adhesion pili. Analysis of the lysogenic properties of the two types of colonies permitted us to propose that simultaneous spontaneous alteration of capsule production and the above-mentioned virulence factors in translucent colonies may be caused by a temperate phage in turbid clones of strain P16064.